ductal hyperplasia

Synopsis

 Proliferating cells form solid sheets, irregular glandular spaces and papillary projections.
 Proliferating cells form sieve-like spaces, so called cribriform pattern.
 In ductal hyperplasia without nuclear atypia, the proliferating cells consists of secretory cells with round to oval nuclei.
 Myoepithelial cells have oval to elongated, slightly hyperchromatic nuclei.
 Mild ductal hyperplasia is three or four cell layers thick.
 The nuclei are normochromatic, oval, with inconspicuous nucleoli and no mitotic activity.
 papillary ductal hyperplasia

• Papillary hyperplasia is part of the spectrum of mild and moderate ductal hyperplasia.
• The papillae are blunt or delicate and irregularly shaped.
• Intraluminal proliferation may create a solid ball of epithelium attached to one side of the duct and surrounded by a cleft-like space - creating an appearance reminiscent of a renal glomerulus.

 In florid ductal hyperplasia with apocrine change, the individual cells have abundant granular eosinophilic cytoplasm and distinct cytoplasmic borders.

 The entire lumen can be filled up by the proliferating ductal epithelial cells.

• The nuclei are oval and normochromatic and mitotic activity is not increased.
• There is no necrosis.
• Several elongated clefts can be present at the periphery and within the cluster.
• There is some streaming effect due to oval nuclei being aligned in parallel bundles.

 In florid ductal hyperplasia, there can be several peripheral elongated clefts.

• They are bound on one side by basally located cells and on the other side by solid intraluminal cluster of epithelal cells.

Differential diagnosis

 mammary atypical ductal hyperplasia

• The proliferating cells form irregular glandular spaces.
• Atypical cells with enlarged, irregular, hyperchromatic nuclei, uneven distribution of chromatin, and medium sized nucleoli.
• Individually, these atypical cells have the characters of malignant cells. However, the background benign epithelial cells and myoepithelial cells remain.
• In these foci, highly atypical cells can become quite homogeneous, however, rare myoepithelial cells with small, dark nuclei remain.
• Solid filling of a duct can be observed.
• In patient with atypical ductal hyperplasia, the risk of invasive breast carcinoma is approximately 5 times that of the general population.
• The cytologic features are indistinguishable from low-grade DCIS (monomorphic cells with round or oval nuclei, micropapillary structures, tufts, fronds, cribriform areas etc).
• But usually they are admixed with ductal hyperplasia or show partial involvement of terminal duct-lobular unit.

See also

 mammary anomalies